Tag Archives: firewall

A fundamental design flaw in network design and access management gives malware an open door into organizations.

Run the information technology clock back to the early 1980s, when universities and businesses began implementing local area networks. We connected ThinNet or ThickNet cabling to our servers and workstations and built the first local area networks, using a number of framing technologies – primarily Ethernet.

By design, Ethernet is a shared medium technology, which means that all stations on a local area network are able to communicate freely with one another. Whether devices called “hubs” were used, or if stations were strung together like Christmas tree lights, the result was the same: a completely open network with no access restrictions at the network level.

Fast forward a few years, when network switches began to replace hubs. Networks were a little more efficient, but the access model was unchanged – and remains so to this day. The bottom line:

Every workstation has the ability to communicate with every other workstation on all protocols.

This is wrong. This principle of open internal networks goes against the grain of the most important access control principle: deny access except when explicitly required. With today’s internal networks, there is no denial at all!

What I’m not talking about here is the junction between workstation networks and data center networks. Many organizations have introduced access control, primarily in the form of firewalls, and less often in the form of user-level authentication, so that internal data centers and other server networks are no longer a part of the open workstation network. That represents real progress, although many organizations have not yet made this step. But this is not the central point of this article, so let’s get back to it.

There are two reasons why today’s internal networks should not be wide open like most are now. The first reason is that it facilitates internal resource sharing. Most organizations have policy that prohibits individual workstations from being used to share resources with others. For instance, users can set up file shares and also share their directly-connected printers to other users. The main reason this is not a great idea is that these internal workstations contribute to the Shadow-IT problem by becoming non-sanctioned resources.

The main objection to open internal networks is that they facilitate the lateral movement of malware and intruders. For fifteen years or more, tens of thousands of organizations have been compromised by malware that self-propagates through internal networks. Worms such as Code Red, Nimda, Slammer, and Blaster scan internal networks to find other opportunities to infect internal systems. Attackers who successfully install RATs (remote access Trojans) on victim computers can scan local networks to enumerate internal networks and select additional targets. Today’s internal networks are doing nothing to stop these techniques.

The model of wide-open access needs to be inverted, so that the following rules of network access are implemented:

Workstations have no network access with each other.

Workstations have access ONLY to servers and services as required.

This should be the new default; this precisely follows the access control principle of deny all except that which is specifically required.

Twenty years ago, this would have meant that all workstation traffic would need to traverse firewalls that would made pass or no-pass decisions. However, in my opinion, network switches themselves are the right place to enact this type of access control.

The late-year holidays (Thanksgiving, Hanukkah, Christmas) are known for travel, visiting with friends and family, and gift giving and receiving. Any time of year is a time for sharing some details of our lives with others through social media outlets such as FaceBook, Twitter, MySpace, and personal blogs.

During this time of year, it is especially important that you protect yourself from online threats, some of which are caused by others, and some of which are caused by you! Follow these steps to keep your property and your online presence safe during the holidays:

Don’t announce your travel in advance. If you post something like, “leaving home for Philadelphia for five days”, you are announcing to the world that your home may be vacant for extended periods of time, inviting burglaries. Make your posts more vague, such as “spending Christmas with brothers and parents”, which might be where you live, or not.

Don’t gloat about your gifts. Similarly, if you talk about your new Kinect, Wii, or iPad online, you may be sharing news of your loot with too many outsiders. Instead, be more discrete and share news about your new things more privately.

Limit FaceBook exposure. Check your privacy settings in FaceBook. Consider setting up one or more groups of family and friends, to limit how wide your announcements are sent. My wife and I have “immediate family”, “family”, and other groups of highly-trusted individuals with whom we may share things about travel, gifts, and other personal matters, so that the entire world doesn’t know that we might not be home at the moment. Similarly, limit the FaceBook applications that you allow to access your personal data. Some FaceBook applications are malevolent and are designed to steal your information and use it against you.

Get a security tune-up. Follow easy steps to ensure that your anti-virus and firewall are working, and that your patches and browser are up to date. Do this before you shop online, to limit the chances that your credit cards will be compromised.

Secure your home Wi-Fi. Find the instructions to improve the security of your home router or Wi-Fi access point. Change from no security to WEP, or better yet, WPA. While WEP is not as secure these days, it’s better than nothing. WPA or WPA2 are far better, and most PCs (and even gaming consoles) supports WPA and WPA2 these days.

Limit use of public Wi-Fi hotspots. From road warriors to housewives, we roam with our laptops from hotspot to hotspot at our favorite coffee shops and other public venues. While it’s okay to check the news and get shopping information, it is not okay to check e-mail, log on to FaceBook or Twitter, or perform high-value activities such as online shopping from an open WiFi hotspot. Easy to use tools are widely available that permit even the unskilled to hijack your session and compromise your personal information.

Check your credit. U.S. consumers can check their credit three times per year for free (once per year for each of the three credit bureaus). Check your credit report carefully, looking for any accounts that you may not have opened, or for changes in accounts you may not have authorized.

Use a separate online shopping credit card. Rather than using your primary credit/debit card for online shopping, open a second account and use only that one. Keep a low balance to minimize your exposures.

Choose “credit” when using debit/credit cards. Whenever you are making purchases with your debit/credit card, choose “Credit”. Then, if your credit card number is later compromised, you may enjoy additional protection (such as the $50 liability limit) on your account. Many banks do not offer the same protection for compromised debit card numbers.

Then run a scan of your entire computer. Double-click the AVG anti-virus icon in the systray. Click Test Center, then click Scan Computer. This will take a while – now you can watch the game.

Do an Online Virus Scan

Not sure if your installed anti-virus program is finding all the viruses on your computer? Go to one or more of these sites to get a free online scan – like getting a second opinion on the health of your computer.

Any of these will take just a few minutes to set up, and then the scan will take as long as an hour or more. Enjoy the game while the scan is running.

Install a Free Personal Firewall

A firewall can block incoming threats like worms and bots that can otherwise harm your system and steal your data. Like the other tools on this page, these two products are both free. Firewalls require a little more knowledge, so you might want to find a power-user friend to help.

Install one or two of these packages, then follow the instructions to scan your entire computer for spyware.

Install Software Patches

Okay, software patches should be free, and free they are. It is very important to stay up to date with Windows and Office security patches. If you run Windows, get your patches straight from Microsoft. Unless you’re an IT pro, I recommend you set up Automatic Updates so that patches are installed automatically.

U.S. citizens can get free credit checks once per year. You can get them from all three credit reporting bureaus all at once, or do one every four months, picking a different bureau every time. By monitoring your credit, you are more likely to discover fraudulent use of your identity.

You might have a firewall already and not know it – your DSL or Cable modem may have a firewall built-in. Look on the label to see what kind of device you have. Log in to your Internet provider’s web site and check whether your modem has a built-in firewall. If it doesn’t, ask to be upgraded.

If you have a laptop computer and access the Internet via WiFi “hotspots” in cafes, libraries, or other locations, you need a firewall even if your home router has a firewall built-in.

You can also install a personal firewall program on each PC in your house. If you have Windows XP or Vista, a firewall is provided with Windows but you need to activate it.

I have an idea for a New Year’s resolution this year. You’ll still be able to eat what you want and walk by the bathroom scale with no pangs of guilt, and you can leave your mess in the garage and the junk drawer so full you can barely open it.

Make your computing safer in 2008. This is a lot easier than you think. You’ll be protecting yourself against potentially painful experiences such as credit card fraud and identity theft.

Follow these steps. In some cases, I’ll link you back to tips I’ve written in the past couple of years.

1. Protect your computers with a firewall. You might have a firewall already and not know it – your DSL or Cable modem may have a firewall built-in. Look on the label to see what kind of device you have. Log in to your Internet provider’s web site and check whether your modem has a built-in firewall. If it doesn’t, ask to be upgraded.

You can also install a personal firewall program on each PC in your house. If you have Windows XP or Vista, a firewall is provided with Windows but you need to activate it.

Test your firewall to see if it is working: Site 1: (www.auditmypc.com), Site 2: (www.grc.com/) (You can consider these to be trusted web sites).

2. Get the spyware out and keep it out. Spyware is used to snoop on your PC and Internet usage – most people find it offensive and a violation of their privacy. Install one or more of the following anti-spyware programs. Scan your computer now, then scan monthly after that.

3. Keep your PC’s security patches up to date. Failure to install security patches is a major cause of computer break-ins, especially for home computers, most of which are not protected by firewalls. I recommend you take a look at your Windows Automatic Updates setting and change the settings so that security patches are downloaded and installed automatically (if you are more of a “hands on” computer user, then you should set Automatic Updates to automatically download security patches and then inform / ask you to install them).

4. Make separate user accounts for shared computers. If any of your computers are shared among family members, make separate user accounts for each user. Put passwords on each account and do not share your passwords. Make only one account an “administrator” (you – since you are reading this!) and make all other users a “Limited account”. Turn off the Guest account.

When a family member is done with the computer (even for a minute), get everyone into the habit of locking the screen, which requires a password to unlock. Click here for instructions.

5. Change your Wireless network to WPA. I have written in the past about how the old wireless WEP protocol is no longer safe. You need to upgrade your WiFi access point and the computers in your house that use WiFi from WEP to WPA. The WEP protocol that is still the default on most WiFi access points and routers can be easily broken by any clever computer user with a few simple tools.

6. Clean out your old programs. Take some time to remove old programs that you no longer use, and upgrade the programs and plug-ins you do use to current versions. In Windows XP, go to My Computer > Control Panel > Add or Remove Programs (in Vista it’s slightly different) and remove each program you no longer need. Maybe you have old toolbars and other things you tried out but didn’t like. It’s a good idea to just get rid of them here.

Consider getting a copy of Secunia Personal Software Inspector (PSI). This nifty program will look at all of your installed programs and tell you which ones are old and unsecure. PSI will also tell you what patches are needed on your system.

7. Learn more about safe computing. Order a copy of Computer Viruses for Dummies – this is a smaller-format Dummies book that talks about Viruses and also spam, spyware, firewalls, and other steps you need to take to make your computer safer.

Internet use can be far safer for most home computer users through the use of free tools and services that help protect computers from malicious code that can lead to identity theft and fraud. In this article:

Free anti-virus

Free online virus scan

Free DNS filtering

Free personal firewall

Free rootkit detection

Free anti-spyware

Free patch updates

Free file eraser

Free disk encryption

Free password storage

Free encrypted e-mail

Free credit check

All of the tools represent the best of the best – they are all popular and renounced for their quality and effectiveness. If you doubt any of these, google these topics yourself and see where these tools appear in your search results.

Note: I have been using many of these tools for years, and am very happy with them. Data security is my profession; I am paid to know this stuff. Happy Holidays!

Free Anti-Virus

Most users don’t need fee-based anti-virus programs like Norton or McAfee. Instead, consider using AVG anti-virus. It’s free, easy to install and use, and just as effective as the big boys.

AVG from Grisoft: www.grisoft.com (you’ll have to hunt around on their site to find the free version. Keep looking.)

Free Online Virus Scan

Not sure if your installed anti-virus program is finding all the viruses on your computer? Go to one or more of these sites to get a free online scan – like getting a second opinion on the health of your computer.

A firewall can block incoming threats like worms and bots that can otherwise harm your system and steal your data. Like the other tools on this page, these two products are both free. Firewalls require a little more knowledge, so you might want to find a power-user friend to help.

Okay, software patches should be free, and free they are. It is very important to stay up to date with Windows and Office security patches. If you run Windows, get your patches straight from Microsoft. Unless you’re an IT pro, I recommend you set up Automatic Updates so that patches are installed automatically.

Did you know that “deleting” files on your Windows computer doesn’t really delete the information at all? It’s still there for any clever intruder to find – even after you empty your trash can. This free tool called Eraser safely *wipes* your deleted data so that it cannot be discovered. Read this tip.

If your laptop (or desktop) computer is stolen, thieves are going to be able to steal all of the data on your hard drive. You can encrypt your hard drive, which will result in thieves being unable to access your data. Read this tip.

I have mentioned in the past that you need to be careful how and where you store your passwords. If you store them in your computer, intruders can find and exploit them by logging in to your websites. Please do not use your browser to store passwords! Instead, use one of these two free tools to securely store passwords. More info here.

If you are sometimes concerned that a third-party may be able to read your e-mail – you’re right and you’re not alone. Sending e-mail is like sending postcards through the mail: others can easily see what you are saying to your friends and colleagues. Hushmail safely encrypts e-mail with world-renowned PGP (and your power-user friends who use PGP can send and receive encrypted mail with you). Best of all, it’s free, like the other tools on this site.

U.S. citizens can get free credit checks once per year. You can get them from all three credit reporting bureaus all at once, or do one every four months, picking a different bureau every time. By monitoring your credit, you are more likely to discover fraudulent use of your identity.

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Ethics Disclaimer

My professional codes of ethics ((ISC)², ISACA, InfraGard) forbid me from activities that give even the appearance of impropriety. Hence, I do not possess, and never have possessed, nor downloaded, examined, or viewed, any tools that can be used to exploit weaknesses. I do not associate with those who do. I am 100% white hat.